From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mm01.cs.columbia.edu (mm01.cs.columbia.edu [128.59.11.253]) by smtp.lore.kernel.org (Postfix) with ESMTP id C4B51C46467 for ; Tue, 29 Nov 2022 21:15:34 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id 3E3414B3D1; Tue, 29 Nov 2022 16:15:34 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Authentication-Results: mm01.cs.columbia.edu (amavisd-new); dkim=softfail (fail, message has been altered) header.i=@linux.dev Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id f0Cm9YzFtPa3; Tue, 29 Nov 2022 16:15:32 -0500 (EST) Received: from mm01.cs.columbia.edu (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id D678940F30; Tue, 29 Nov 2022 16:15:32 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id E9DC640AFA for ; Tue, 29 Nov 2022 16:15:31 -0500 (EST) X-Virus-Scanned: at lists.cs.columbia.edu Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id LvyFMpCeJ0LN for ; Tue, 29 Nov 2022 16:15:26 -0500 (EST) Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id B3C6040F30 for ; Tue, 29 Nov 2022 16:15:26 -0500 (EST) Date: Tue, 29 Nov 2022 21:15:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1669756525; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FtYFpXu5/fa0TaYiI4P0+GO9iWhqJmCXUsHphTqwjGw=; b=oE86JcLcGxsicJ5+/muPqhDr7FrTiNs6WD8LcTD34Qo6fvG4ULczduWra99AnJWXD8Xtg0 garTf7J0LX7RmBFNAhjKicG/NVDNgHM7JNlVsJIgPMT0ZyHg3SMpR3SR8h5DHbZkmS+wfD UYYEx/SftPydGa+lK+iguxXp2/OPh14= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Ricardo Koller Subject: Re: [PATCH 2/4] KVM: arm64: Don't serialize if the access flag isn't set Message-ID: References: <20221129191946.1735662-1-oliver.upton@linux.dev> <20221129191946.1735662-3-oliver.upton@linux.dev> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT Cc: kvm@vger.kernel.org, Marc Zyngier , linux-kernel@vger.kernel.org, Catalin Marinas , kvmarm@lists.linux.dev, Will Deacon , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu Hi Ricardo, Thanks for having a look. On Tue, Nov 29, 2022 at 12:52:12PM -0800, Ricardo Koller wrote: > On Tue, Nov 29, 2022 at 07:19:44PM +0000, Oliver Upton wrote: [...] > > + ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, > > + &pte, NULL, 0); > > + if (!ret) > > + dsb(ishst); > > At the moment, the only reason for stage2_update_leaf_attrs() to not > update the PTE is if it's not valid: > > if (!kvm_pte_valid(pte)) > return 0; > > I guess you could check that as well: > > + if (!ret || kvm_pte_valid(pte)) > + dsb(ishst); Thanks for catching this. Instead of pivoting on the returned PTE value, how about we return -EAGAIN from the early return in stage2_attr_walker()? It would better match the pattern used elsewhere in the pgtable code. -- Thanks, Oliver _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out2.migadu.com (out2.migadu.com [188.165.223.204]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8A2B0BA28 for ; Tue, 29 Nov 2022 21:15:27 +0000 (UTC) Date: Tue, 29 Nov 2022 21:15:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1669756525; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FtYFpXu5/fa0TaYiI4P0+GO9iWhqJmCXUsHphTqwjGw=; b=oE86JcLcGxsicJ5+/muPqhDr7FrTiNs6WD8LcTD34Qo6fvG4ULczduWra99AnJWXD8Xtg0 garTf7J0LX7RmBFNAhjKicG/NVDNgHM7JNlVsJIgPMT0ZyHg3SMpR3SR8h5DHbZkmS+wfD UYYEx/SftPydGa+lK+iguxXp2/OPh14= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Ricardo Koller Cc: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] KVM: arm64: Don't serialize if the access flag isn't set Message-ID: References: <20221129191946.1735662-1-oliver.upton@linux.dev> <20221129191946.1735662-3-oliver.upton@linux.dev> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT Message-ID: <20221129211521.domT0FWh7AhJfCbpFTU1LEQLuHF4vt9mfGMymwdqihE@z> Hi Ricardo, Thanks for having a look. On Tue, Nov 29, 2022 at 12:52:12PM -0800, Ricardo Koller wrote: > On Tue, Nov 29, 2022 at 07:19:44PM +0000, Oliver Upton wrote: [...] > > + ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, > > + &pte, NULL, 0); > > + if (!ret) > > + dsb(ishst); > > At the moment, the only reason for stage2_update_leaf_attrs() to not > update the PTE is if it's not valid: > > if (!kvm_pte_valid(pte)) > return 0; > > I guess you could check that as well: > > + if (!ret || kvm_pte_valid(pte)) > + dsb(ishst); Thanks for catching this. Instead of pivoting on the returned PTE value, how about we return -EAGAIN from the early return in stage2_attr_walker()? It would better match the pattern used elsewhere in the pgtable code. -- Thanks, Oliver From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 80FF8C433FE for ; Tue, 29 Nov 2022 21:16:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=poUWkARc1O9wzS4/8Dkglg5wJ/IqsbpKI5gaC3YYdS8=; b=ExJp5MpU27Xx6m qTSMvchEhRlv/3qnZq8hzN59DU+QqeMTR6v78711dULMXeq6e5Ps8yG3ElKVK5QWU/Zeu3oWCiQcm qGVt5aVLf9DfrrHGK803tr9opicgakNFcmHHV66lfj9ybSnQk7hK4rH/7nRBeYS1VM1Fty4Rll+HO YJLGH65cOC67YZyDc4BhKqfWNRsH61dygzvsOZWDOkLPbCIQpfJpy01S+pefthtepvEYY8SGdPg/m wHufEL7wuSZ47EBzKsL3nwhYn0iQ+Q8zB65zb2qg73PTJmY+8LAvLh6xOA5K1o0gCXE+cVbX6G3IL Z6IFo6hcGk5m25qcIJEA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1p07xA-00BN5m-HN; Tue, 29 Nov 2022 21:15:44 +0000 Received: from out2.migadu.com ([188.165.223.204]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1p07x7-00BN1Q-BN for linux-arm-kernel@lists.infradead.org; Tue, 29 Nov 2022 21:15:42 +0000 Date: Tue, 29 Nov 2022 21:15:21 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1669756525; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FtYFpXu5/fa0TaYiI4P0+GO9iWhqJmCXUsHphTqwjGw=; b=oE86JcLcGxsicJ5+/muPqhDr7FrTiNs6WD8LcTD34Qo6fvG4ULczduWra99AnJWXD8Xtg0 garTf7J0LX7RmBFNAhjKicG/NVDNgHM7JNlVsJIgPMT0ZyHg3SMpR3SR8h5DHbZkmS+wfD UYYEx/SftPydGa+lK+iguxXp2/OPh14= X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Oliver Upton To: Ricardo Koller Cc: Marc Zyngier , James Morse , Alexandru Elisei , Suzuki K Poulose , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/4] KVM: arm64: Don't serialize if the access flag isn't set Message-ID: References: <20221129191946.1735662-1-oliver.upton@linux.dev> <20221129191946.1735662-3-oliver.upton@linux.dev> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Migadu-Flow: FLOW_OUT X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20221129_131541_556062_03030FC0 X-CRM114-Status: GOOD ( 13.77 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Ricardo, Thanks for having a look. On Tue, Nov 29, 2022 at 12:52:12PM -0800, Ricardo Koller wrote: > On Tue, Nov 29, 2022 at 07:19:44PM +0000, Oliver Upton wrote: [...] > > + ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0, > > + &pte, NULL, 0); > > + if (!ret) > > + dsb(ishst); > > At the moment, the only reason for stage2_update_leaf_attrs() to not > update the PTE is if it's not valid: > > if (!kvm_pte_valid(pte)) > return 0; > > I guess you could check that as well: > > + if (!ret || kvm_pte_valid(pte)) > + dsb(ishst); Thanks for catching this. Instead of pivoting on the returned PTE value, how about we return -EAGAIN from the early return in stage2_attr_walker()? It would better match the pattern used elsewhere in the pgtable code. -- Thanks, Oliver _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel